Technical Field
This disclosure relates to computer networking. More specifically, this disclosure relates to methods and apparatuses for path selection.
Related Art
Enterprise networks can include one or more wide-area networks (WANs) that interconnect offices that can be distributed over a large geographical area. Some enterprise networks use WAN optimization devices to improve network performance. WAN optimization devices optimize network traffic to improve WAN performance in reading and/or writing data over a network. Some WAN optimization devices monitor users' network traffic to attempt to predict data likely to be requested by users. This predicted data is prefetched over the WAN and cached by the WAN optimization devices at the users' respective network locations, so that this data can be quickly accessed by users if requested. WAN optimization devices also typically compress data (e.g., by performing de-duplication) to improve WAN performance. The WAN optimization devices' prefetching, caching, and compression helps mask the bandwidth and latency limitations of WANs from users.
WAN optimization devices may operate singly or in pairs at each side of a WAN connection to optimize network traffic. WAN optimization devices are referred to in the art by many different terms, including, but not limited to, transaction accelerators, WAN optimizers, WAN optimization controllers (WOCs), wide-area data services (WDS) appliances, WAN traffic optimizers (WTOs), and protocol accelerators or optimizers.
Techniques for optimizing network traffic to improve network performance in reading and/or writing data over a network are referred to in the art by many different terms, including, but not limited to, WAN acceleration, transaction acceleration, transaction pipelining, protocol pipelining, request prediction, application flow acceleration, and protocol acceleration. In this disclosure, the term “WAN optimization device” is used to refer to such devices and applications and “WAN optimization” is used to refer to such techniques.
In the hunt for increased performance at lower cost, many information technology (IT) organizations are creating so-called hybrid networks that, like many of today's applications, escape the boundaries of traditional enterprise network infrastructure. In some use cases, the primary multi-protocol label-switching (MPLS) network might connect data center branches and ferry mission-critical work with higher priority, while cheaper virtual private network (VPN) and local Internet lines carry the remainder of traffic. The hybrid network is defined by its mixed use of multiple topologies. While hybrid networks solve important problems, conventional systems and techniques do not enable IT and business to drive and support new applications in the network and establish service level agreements (SLAs) for each application with enough resources at every point of its lifecycle.
Specifically, in conventional approaches, lower-priority branch Internet traffic is typically backhauled along with mission-critical traffic across expensive private networks to the data center, then the low-priority branch Internet traffic exited from the data center to the Internet (typically through a firewall at the data center), and the return traffic would likewise take the circuitous route back to the end user. In such conventional approaches, backup links are often underutilized, and it is not possible to selective route web and cloud services to the Internet directly from the branch location.